The present invention relates to a multiway rotary valve.
The multiway rotary valve includes two valve elements, which interact to direct a pressurized medium to and from two working chambers of at least one servomotor, and to a return connection for a pressurized-media vessel. The two valve elements can rotate relative to each other. One of the two valve elements has a cavity, in which two planar control surfaces facing each other are disposed. The other of the two valve elements is essentially a planar disk, which has two planar control surfaces facing away from each other. The planar control surfaces of the two valve elements have control openings, which interact with each other.
For example, such a multiway rotary valve is described in European Published Patent Application No. 0 145 546. This multiway rotary valve is provided for a power-assisted steering system of a motor vehicle. In this case. A primary component is connected to an input-operation component. A secondary component is assigned to a primary component, via a free-travel connection. The free-travel connection allows a limited, relative movement of the primary and secondary components. Since the primary component is connected to a rotatable input component, the use of such a multiway rotary valve is limited to application, in which a rotatable input component is present, e.g., power-assisted steering systems in motor vehicles.
It is an object of the present invention to provide a multiway rotary valve, which is not limited to use in power-assisted steering systems of motor vehicles. The multiway rotary valve is intended for general use as a control member in hydraulic systems.
The above and other beneficial objects of the present invention are achieved by providing a generic, multiway rotary valve, in which one of the two valve elements can be rotated by a limited amount, using at least one actuating element, the actuator acting upon the valve element in an essentially tangential direction. This design allows the multiway rotary valve to be used freely in various applications, for example, in a motor vehicle.
If the rotatable valve element has the shape of a circle segment, especially a semicircular shape having contact surfaces that are radially aligned, then an actuator may act upon one of the radial contact surfaces. Such an actuator may be in the form of an impacting rod, which may be controlled by an electromagnet. If two of such actuators are used, then the rotatable valve element may be adjusted and centered in both directions of rotation. When using the multiway rotary valve in a motor vehicle, the electromagnets may be energized as a function of at least one parameter. This allows different effects, such as steering angle, vehicle speed, vehicle load, etc., to be considered in controlling the multiway rotary valve.
Such a multiway rotary valve may easily be manufactured, when one of the two valve elements is made of two squeeze-molded, platelike, light-metal housing parts. The necessary control openings may also be pressed into these light-metal housing parts directly, during their manufacture. The other of the two valve elements, the rotatable one, may be formed as a punched, sheet-metal part, or a sintered part. The necessary control openings may be formed automatically during manufacture, e.g., by punching, stamping, or sintering. The two light-metal housing parts and the rotatable part are pivotally interconnected, such as, for example, by a centrally positioned bolt. This arrangement simplifies the assembly allows the planar clearance of the multiway rotary valve, between the control surfaces of the two valve elements, to be corrected in a simple manner. In addition, this arrangement may substantially prevent internal leakage of the multiway rotary valve.
To enlarge the multiway rotary valve, at least one more plate having an additional rotary valve or slide valve may be mounted to the multiway rotary valve. Thus additional functions, such as a hydraulic short-circuiting connection, may be integrated in the multiway rotary valve. An electromagnet for the actuators of the additional rotary valve or slide valve may also be provided.